fix(mangen): Respect more hide values

[tahmid-23]

Respect remaining hidden flags

• Arg::hide_default_value
• Arg::hide_long_help
• Arg::hide_short_help

Fixes #3361

[epage]

(it seems to cover everything?).

Doing another look through, I see that we aren't covering Command::hide_possible_values. Would you like to cover that in this PR or should we defer it out?

[tahmid-23]

that flag propagates to all of the arguments and overrides whatever setting the arguments have, and the individual arguments' hide_possible_values is already correctly handled

[epage]

Thanks for the reminder!

[epage]

This was done in master which corresponds with v4. If you want, you can cherry-pick this into the v3-master branch.